1. Field of the Invention
This invention relates to brazed heat exchangers and more particularly to aluminium alloy composite or clad materials for use in brazed heat exchangers. These materials have improved water corrosion resistance properties and good mechanical strength.
2. Description of the Prior Art
Aluminum alloy brazed heat exchangers are widely used as condensers and evaporators in automobile air conditioners. However, Al alloys are rarely used as members for heat exchangers, such as, for example, in radiator header tubes in which a water coolant is used. The reason for this is that conventional Al alloys have unsatisfactory water corrosion resistance properties. Thus when the quality of the coolant is bad, the alloys are apt to undergo break-through corrosion even in a very short period of time, thereby causing a vital drawback in it's application as a member for heat exchangers. Accordingly, Al alloys which are applied for these purposes are strongly demanded to have improved water corrosion resistance properties. Moreover, there is also a strong demand for these heat exchangers to be light weight. In order to meet this demand, Al alloys should have high strength characteristics sufficient to make thin members.